/*
 *
 * Copyright (c) 2008 Elias Ross
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in 
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 *
 */

package com.nothome.delta.text;

import java.io.IOException;
import java.nio.CharBuffer;

/**
 * Wrapper for a {@link CharBuffer}.
 */
public class CharBufferSeekableSource implements SeekableSource {
    
    private CharBuffer cb;
    private CharBuffer cur;

    /**
     * Constructs a new CharBufferSeekableSource.
     */
    public CharBufferSeekableSource(CharBuffer cb) {
        if (cb == null)
            throw new NullPointerException("cb");
        this.cb = cb;
        try {
            seek(0);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
    
    /**
     * Constructs a new CharBufferSeekableSource from a char sequence (String).
     */
    public CharBufferSeekableSource(CharSequence seq) {
        this(CharBuffer.wrap(seq));
    }

    public void seek(long pos) throws IOException {
        cb.rewind();
        cur = cb.slice();
        if (pos > cur.limit())
            throw new IOException("pos " + pos + " cannot seek " + cur.limit());
        cur.position((int) pos);
    }

    public int read(CharBuffer charbuffer) throws IOException {
        return cur.read(charbuffer);
    }

    public void close() throws IOException {
    }
}
